The growth hormone test measures the amount of growth hormone in the blood.
The pituitary gland makes growth hormone, which causes a child to grow. This gland is located at the base of the brain.
A blood sample is needed.
Your health care provider may give you special instructions about what you can or cannot eat before the test.
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
This hormone may be checked if a person's growth pattern is abnormal or if another condition is suspected.
The GH test may also be used to monitor response to acromegaly treatment.
The normal range for GH level is typically:
GH is released in pulses. The size and duration of the pulses varies with time of day, age, and gender. This is why random GH measurements are rarely useful. A higher level may be normal if the blood was drawn during a pulse. A lower level may be normal if the blood was drawn around the end of a pulse. GH is most useful when measured as part of a stimulation or suppression test.
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different specimens. Talk to your provider about the meaning of your specific test results.
A high level of GH may indicate:
A low level of GH may indicate:
Veins and arteries vary in size from one person to another, and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
Ali O. Hyperpituitarism, tall stature, and overgrowth syndromes. In: Kliegman RM, Stanton BF, St Geme JW, Schor NF, eds. Nelson Textbook of Pediatrics. 20th ed. Philadelphia, PA: Elsevier; 2015:chap 560.
Cooke DW, Divall SA, Radovick S. Normal and aberrant growth in children. In: Melmed S, Polonsky KS, Larsen PR, Kronenberg HM, eds. Williams Textbook of Endocrinology. 13th ed. Philadelphia, PA: Elsevier Saunders; 2016:chap 24.
Maitra A. The endocrine system. In: Kumar V, Abbas AK, Aster JC, eds. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 24.
Last reviewed on: 2/3/2016
Reviewed by: Brent Wisse, MD, Associate Professor of Medicine, Division of Metabolism, Endocrinology & Nutrition, University of Washington School of Medicine, Seattle, WA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.